Slaking is a pretty underrated Pokémon. Mainly because of its ability, Truant, which allows the Pokémon to use a move every few turns. For instance, if you attack one turn, you skip the next turn and choose your next move for the third turn. It really places Slaking into a bad situation but it is a good thing that Slaking has the ability Truant or else it would be to powerful for Pokémon. Base 670 stats! Can you imagine going up against a Slaking if it didn't have the Truant ability? If you want to have a nice powerhouse for RU or UU, then you might take a look at Slaking before you decide.

Steps

Method1

Scarf Slaking

1

Obtain a Slaking. Scarf Slaking is essentially a Slaking that is holding the Choice Scarf which dramatically ups its speeds to do some hefty damage and probably out speed the opponent with its already amazing 100 speed.

2

Give the Slaking a Choice Scarf. The Choice Scarf can be found in the Battle Maison for both X and Y. As said before, it raises the speed incredibly but of course it has its price. The Choice Scarf will up your speed in return for a singular move to be used only. For example, if you had a Garchomp with a Choice Scarf and it went for Outrage, it would most likely be faster than the opponent and land the hit. Then, Garchomp is forced to use Outrage unless it is switched out or fainted.

3

Give it a Jolly Nature. It ups the Speed but lowers the Special Attack, and Slaking isn't much of it anyway.

4

Work on Slaking's stats. Since Slaking is a powerful Pokémon, give it 252 Attack, 252 Speed, and 4 HP. 252 Attack for powerful Giga Impacts, 252 Speed for you to go first, and 4 HP to help Slaking just a bit.

Brick Break - To go against normal/steel types as well as breaks screens.

Sucker Punch - Always go first but only hits if the attacker is using an attacking move.

Other moves could be any of the elemental punches (Fire, Ice, Thunder Punch), or Night Slash since it has a high critical hit ratio.

Method2

Stall Slaking

1

Obtain a Slaking. Stall Slaking is more annoying than Scarf Slaking so it will have more effecting moves.

2

Give the Slaking Leftovers. Leftovers regain your HP after every single turn.

3

Give the Slaking an Impish Nature. Impish ups Defense but lowers Special Attack. Slaking is more of a Defensive/Attacker Pokémon, so Impish would be more beneficial.

4

Work up on Slaking's stats. Give him 252 HP, 252 Defense, and 4 in Attack.

5

Moves for Stall Slaking would be:

Toxic - Toxic Stalling is annoying if the opponent doesn't have any HP recovery moves.

Amnesia - Good Special Defense boost just in case.

Protect - To see what the opponent will do and let the Toxic continue.

Giga Impact - Attacking coverage.

Method3

Façade Slaking

1

Obtain a Slaking. Façade Slaking will have an increased damage of Façade when it is inflicted with a status problem.

2

Give Slaking a Toxic or Flame Orb. Flame Orb is more advised. These orbs gives you the Poison or Burn status problems when held for one turn.

3

Give Slaking a Jolly Nature.

4

Give Slaking 252 Attack, 252 Speed, and 4 Defense.

5

Suggested moves for Façade Slaking are:

Façade - This moves power is doubled when the user is either paralyzed, burned, or poisoned so you can expect a 140 powered, 252 Attack and 252 Speed with Jolly Nature Slaking coming your way!

Bulk Up - Raises Attack and Defense by 1. Good to use when you first send Slaking out as the Flame or Toxic Orb do not activate until one complete turn. So getting the Attack raise will benefit Slaking if it is holding the Flame Orb since Burn lowers Attack.

Pursuit - If the opponent is trying to escape the power of Slaking, predict them with a Pursuit to give the Pokémon switching out lesser HP!

Double-Edge - Powerful move with 33% recoil so be wise on when to use it.